<!-- Button trigger modal -->
<button class="btn btn-primary" data-target="#exampleModal" data-toggle="modal" type="button">
    Launch demo modal
</button>

<!-- Modal -->
<div aria-hidden="true" aria-labelledby="exampleModalLabel" class="modal fade" id="exampleModal" role="dialog"
     tabindex="-1">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
                <button aria-label="Close" class="close" data-dismiss="modal" type="button">
                    <span aria-hidden="true">&times;</span>
                </button>
            </div>
            <div class="modal-body">
                ...
            </div>
            <div class="modal-footer">
                <button class="btn btn-secondary" data-dismiss="modal" type="button">Close</button>
                <button class="btn btn-primary" type="button">Save changes</button>
            </div>
        </div>
    </div>
</div>